This application involves improvements over certain features of the above mentioned patent and patent applications. Specifically this invention provides an improved valve assembly to replace that disclosed in FIGS. 6 and 7 of the incorporated Read patent. Cited portions of the Read patent disclose a valve sleeve having a mandrel with external gudgeon pins and a pair of ports spaced 180.degree. apart around the valve.
An elastomeric seal sleeve is located on the inside surface of the valve sleeve. Although the valve assembly of the Read patent is a significant improvement over the existing art and performs well, it was desirable to obtain a valve assembly having seals with great sealing ability but with reduced resistance to rotation.
This invention provides such a valve assembly by utilizing elastomeric loop seals, which are retained on the seal mandrel by an internal island and by a seal housing slidable onto the seal mandrel.